Systematic review of respiratory viral pathogens identified in adults with community-acquired pneumonia in Europe

Community-acquired pneumonia (CAP) is an important respiratory disease and the fifth leading cause of mortality in Europe. The development of molecular diagnostic tests has highlighted the contributions of respiratory viruses to the aetiology of CAP, suggesting the incidence of viral pneumonia may have been previously underestimated. We performed a systematic review and meta-analysis to describe the overall identification of respiratory viruses in adult patients with CAP in Europe, following PRISMA guidelines (PROSPERO; CRD42016037233). We searched EMBASE, MEDLINE, CINAHL, WHOLIS, COCHRANE library and grey literature sources for relevant studies, and screened these against protocol eligibility criteria. Two researchers performed data extraction and risk of bias assessments, independently, using a piloted form. Results were synthesised narratively, and random effects meta-analyses performed to calculate pooled estimates of effect; heterogeneity was quantified using I². Twenty-eight studies met inclusion criteria of which 21 were included in the primary meta-analysis. The pooled proportion of patients with identified respiratory viruses was 22.0% (95% CI: 18.0%–27.0%), rising to 29.0% (25.0%–34.0%) in studies where polymerase chain reaction (PCR) diagnostics were performed. Influenza virus was the most frequently detected virus in 9% (7%–12%) of adults with CAP. Respiratory viruses make a substantial contribution to the aetiology of CAP in adult patients in Europe; one or more respiratory viruses are detected in about one quarter of all cases.     

Etiology of community‐acquired pneumonia in 1500 hospitalized children

Childhood community‐acquired pneumonia (CAP) is a common illness; however, comprehensive studies of hospitalizations for CAP among children in China based on prospective and multicenter data collection are limited. The aim of this investigation was to determine the respiratory pathogens responsible for CAP in hospitalized children. From January to December 2015, oropharyngeal swabs and blood serum were collected from hospitalized children with CAP symptoms ranging in age from 6 months to 14 years at 10 hospitals across China. We used immunofluorescence to detect antibodies for eight respiratory viruses and passive agglutination to detect specific IgM against Mycoplasma pneumoniae (M. pneumoniae). Of 1500 children presenting with CAP, 691 (46.1%) tested positive for at least one pathogen (virus or M. pneumoniae). M. pneumoniae (32.4%) was detected most frequently, followed by respiratory syncytial virus (11.5%), adenovirus (5.0%), influenza A virus (4.1 %), influenza B virus (3.4%), parainfluenza virus types 2 and 3 type (3.1 %), parainfluenza virus type 1 (2.9%), and human metapneumovirus (0.3%). Co‐infections were identified in 128 (18.5%) of the 691 cases. These data provide a better understanding of viral etiology and M. pneumoniae in CAP in children between 6 months and 14 years in China. More study of the etiologic investigations that would further aid the management of pneumonia is required. With effective immunization for RSV, ADV, and M. pneumoniae infections, more than one‐half of the pneumonia cases in this study could have been prevented.

     

Assessment of analysis of urinary pneumococcal antigen by immunochromatography for etiologic diagnosis of community-acquired pneumonia in adults

The limitations of conventional microbiologic methods (CMM) for etiologic diagnosis of community pneumococcal pneumonia have made faster diagnostic techniques necessary. Our aim was to evaluate the usefulness of the immunochromatography (ICT) technique for detecting urinary Streptococcus pneumoniae antigen in the etiologic diagnosis of community-acquired pneumonias (CAP). This was a prospective study on in-patients with CAP in a tertiary hospital conducted from October 2000 to March 2004. Apart from using CMM to reach an etiologic diagnosis, we determined pneumococcal antigen in concentrated urine by ICT. We also determined the urinary pneumococcal antigen (UPA) content in patients from two control groups to calculate the specificity of the technique. One group was comprised of in-patients diagnosed with chronic obstructive pulmonary disease (COPD) or asthma, with respiratory infection, and without pneumonia; the other group included fractures. We studied 959 pneumonia patients and determined UPA content in 911 (95%) of them. We diagnosed the etiology of 253 cases (28%) using CMM; S. pneumoniae was the most common etiologic agent (57 cases). ICT analysis was positive for 279 patients (31%). Using this technique, the percentage of diagnoses of pneumococcal pneumonias increased by 26%, while the overall etiologic diagnosis increased from 28 to 49%. The technique sensitivity was 81%; the specificity oscillated between 80% in CAP with nonpneumococcal etiology and 99% for patients with fractures without infections. Determination of UPA is a rapid, simple analysis with good sensitivity and specificity, which increased the percentage of etiologic diagnoses. Positive UPA may persist in COPD patients with probable pneumococcal colonization or recent pneumococcal infections.     

Aetiology of lower respiratory tract infection in adults in primary care: a prospective study in 11 European countries

ObjectivesTo describe the role of bacteria (including bacterial resistance), viruses (including those recently described) and mixed bacterial–viral infections in adults presenting to primary care with lower respiratory tract infection (LRTI).MethodsIn all, 3104 adults with LRTI were enrolled, of whom 141 (4.5%) had community-acquired pneumonia (CAP), and 2985 matched controls in a prospective study in 16 primary care networks in Europe, and followed patients up at 28–35 days. We detected Streptococcus pneumoniae and Haemophilus influenzae and assessed susceptibility, atypical bacteria and viruses.ResultsA potential pathogen was detected in 1844 (59%) (in 350 (11%) bacterial pathogens only, in 1190 (38%) viral pathogens only, and in 304 (10%) both bacterial and viral pathogens). The most common bacterial pathogens isolated were S. pneumoniae (5.5% overall, 9.2% in CAP patients) and H. influenzae (5.4% overall, 14.2% in CAP patients). Less than 1% of S. pneumoniae were highly resistant to penicillin and 12.6% of H. influenzae were β-lactamase positive. The most common viral pathogens detected were human rhinovirus (20.1%), influenza viruses (9.9%), and human coronavirus (7.4%). Influenza virus, human parainfluenza viruses and human respiratory syncytial virus as well as human rhinovirus, human coronavirus and human metapneumovirus were detected significantly more frequently in LRTI patients than in controls.ConclusionsA bacterial pathogen is identified in approximately one in five adult patients with LRTI in primary care, and a viral pathogen in just under half, with mixed infections in one in ten. Penicillin-resistant pneumococci and β-lactamase-producing H. influenzae are uncommon. These new findings support a restrictive approach to antibiotic prescribing for LRTI and the use of first-line, narrow-spectrum agents in primary care.     

The epidemiology and etiologies of respiratory tract infection in Northern Taiwan during the early phase of coronavirus disease 2019 (COVID-19) outbreak

BackgroundCoronavirus disease 2019 (COVID-19) manifests symptoms as common etiologies of respiratory tract infections (RTIs). During the pandemic of COVID-19, identifying the etiologies correctly from patients with RTI symptoms was crucial in not only disease control but preventing healthcare system from collapsing. By applying sensitive PCR-based molecular assays, we detected the etiologic agents and delineated the epidemiologic picture of RTIs in the early phase of COVID-19 pandemic.MethodsFrom December 2019 to February 2020, we screened patients presented with RTIs using multiplex PCR-based diagnostic assays. Data from pediatric and adult patients were compared with different months and units in the hospital.ResultsOf all 1631 patients including 1445 adult and 186 pediatric patients screened, 8 viruses and 4 bacteria were identified. Positive rates were 25% in December, 37% in January, and 20% in February, with pediatric patients having higher positive rates than adults (Ps < 0.001). In pediatric patients, RhV/EnV was the most commonly detected, followed by parainfluenza viruses. Most Mycoplasma pneumoniae infection occurred in pediatric patients. RhV/EnV was the most commonly detected agent in pediatric patients admitted to intensive care units (ICUs), while influenza accounted for the majority of adult cases with critical illness. Noticeably, seasonal coronavirus ranked second in both adult and pediatric patients with ICU admission.ConclusionWhile we focused on the pandemic of COVID-19, common etiologies still accounted for the majority of RTIs and lead to severe diseases, including other seasonal coronaviruses.     

Clinical practice of respiratory virus diagnostics in critically ill patients with a suspected pneumonia: A prospective observational study

BackgroundClinical guidelines suggest testing for respiratory viruses during the influenza season, but are unclear which categories of patients on the intensive care unit (ICU) should be tested.ObjectiveWe described the clinical practice of diagnostic testing for respiratory virus infections in patients presenting to ICU with suspected community-acquired pneumonia (CAP) or hospital-acquired pneumonia (HAP).Study designProspective observational study in consecutive CAP and HAP patients with an ICU stay of more than 24 h in two tertiary care hospitals in The Netherlands, from 2011 to December 2013. The proportion of patients receiving diagnostic testing with PCR for the presence of respiratory viruses in respiratory tract specimens was determined.ResultsIn total, 1452 patients were included, of which 712 patients presented with CAP and 740 with HAP. In CAP, 282 of 712 (40%) were tested for respiratory viruses (190 of 417 (46%) during the influenza season). In HAP, 95 of 740 (13%) were tested (50 of 372 (13%) during the influenza season). Regardless of the season, virus diagnostic tests were ordered significantly more often in patients with comorbidities, and in those presenting with elevated CRP and leucopenia. In patients who were tested during the influenza season, the prevalence of influenza was 14% in patients with CAP and 10% in those with HAP. Influenza was absent during the summer in both groups.ConclusionsLess than half of patients admitted to the ICU with suspected pneumonia were tested for the presence of viral pathogens, either in or outside the influenza season.     

Prevalence of human metapneumovirus among hospitalized children younger than 1 year in Catalonia, Spain

Human metapneumovirus was discovered recently respiratory virus implicated in both upper and lower respiratory tract infection. In children, the clinical symptoms of human metapneumovirus are similar to those produced by respiratory syncytial virus, ranging from mild to severe diseases such as bronchiolitis and pneumonia. The aim of the present study was to describe the prevalence of human metapneumovirus and other common respiratory viruses among admitted to hospital infants. From January 2006 to June 2006, 99 nasopharyngeal aspirates were collected from hospitalized children younger than 12 months in order to study respiratory viruses. Human metapneumovirus detection was performed by cell culture and two RT-PCR targeting on polymerase and fusion genes. The latter gene was used for phylogenetic analysis. In 67/99 children (67%) at least one viral pathogen was identified, the viruses detected most frequently were respiratory syncytial virus (35%), human metapneumovirus (25%) and rhinovirus (19%). The results obtained in this study, show that: (1) human metapneumovirus is one of the most important viruses among children less than 12 months; (2) children infected with human metapneumovirus were significantly older than those infected by respiratory syncytial virus; (3) human metapneumovirus was associated more frequently with pneumonia whereas respiratory syncytial virus was only detected in patients with bronchiolitis; (4) there was a clear epidemiological succession pattern with only a small overlap among the viruses detected most frequently; (5) all human metapneumovirus samples were clustered within sublineage A2.     

Clinical evaluation of multiplex real-time PCR panels for rapid detection of respiratory viral infections

Respiratory viral infections are one of the leading causes of morbidity and mortality, particularly in children, the elderly and immunocompromised persons. Rapid identification of viral etiology is critical in ruling out non-viral infections, initiating antiviral treatment and limiting the spread of the infection. Multiplex assays of more than one viral gene target in a single tube have the advantage of rapid screening of a large number of potential viral pathogens in a short time. A multiplex real-time PCR assay was used in this study for detection of respiratory RNA and DNA viral infections in 728 specimens received from 585 adult and pediatric patients comprised of symptomatic and asymptomatic organ transplant recipients and non-recipients for diagnosis of respiratory illnesses and for routine clinical monitoring. Multiplex PCR was more sensitive than the multiplex immunofluoresence culture assay (R-mix) and also detected additional respiratory viruses that were not covered by the R-mix panel. The number of respiratory viruses detected in symptomatic patients was significantly higher than asymptomatic patients in both adult and pediatric patients. Herpesviral infections were the predominant cause of lower respiratory tract infection in the organ transplant recipients, whereas respiratory syncytial virus was the most common pathogen in non-transplant patients particularly children. Multiplex real-time PCR for detection of respiratory viruses has the potential for rapid identification of viral pathogens. In this era of emerging viral infections, addition of newer viral targets to the multiplex PCR panels will be beneficial in determining both patient management and public health epidemiology.     

The impact of 13-valent pneumococcal conjugate vaccination on virus-associated community-acquired pneumonia in elderly: Exploratory analysis of the CAPiTA trial

ObjectivesOur objective was to evaluate whether vaccination with the 13-valent pneumococcal conjugate vaccine (PCV13) prevents the incidence of community-acquired pneumonia (CAP) caused by influenza (influenza-associated CAP, IA-CAP) or other respiratory viruses in the elderly.MethodsThis analysis was part of the Community-Acquired Pneumonia immunization Trial in Adults (CAPiTA); a double blind, randomized, placebo-controlled trial in 84 496 immunocompetent individuals aged ≥65 years. CAP was defined by clinical and radiological criteria, and oropharyngeal swabs were collected from all individuals referred to a sentinel centre with a clinical suspicion of pneumonia. Presence of influenza A and B, parainfluenza 1, 2, 3 and 4, human adeno-, boca-, corona-, metapneumo-, rhino- and respiratory syncytial viruses was determined by real-time PCR.ResultsOf 3209 episodes of suspected pneumonia, viral aetiology was tested in 2917 and proportions with influenza virus, human metapneumovirus and respiratory syncytial virus were 4.6%, 2.5% and 3.1%, respectively. There were 1653 oropharyngeal swabs for PCR testing available from 1814 episodes that fulfilled criteria for CAP, yielding 23 first episodes of IA-CAP in the PCV13 and 35 in the in placebo group—vaccine efficacy for IA-CAP of 34.4% (95% CI –11.1% to 61.2%; p 0.117). Annual influenza vaccination was received by 672 (87.2%) in the PCV13 group and 719 (87.7%) in the placebo group of the confirmed CAP cases.ConclusionIn a randomized study of 84 496 elderly individuals with a high uptake of influenza vaccination, PCV13 was not associated with a statistically significant reduction of influenza or virus-associated CAP. Overall incidence of non-influenza viral pneumonia was low.     

Low prevalence of Chlamydia pneumoniae in adults with community-acquired pneumonia

The incidence of community-acquired pneumonia (CAP) due to Chlamydia pneumoniae was determined in a prospective study of 546 adult patients with CAP included in the German CAP Competence Network (CAPNETZ) project. Three different PCR protocols for detection of C. pneumoniae in respiratory specimens were compared by a multicenter, inter-laboratory comparison involving three laboratories. A case was defined as a patient with a respiratory sample positive by PCR in at least two laboratories. CAP was caused by C. pneumoniae in 5/546 cases (0.9%). Antibody testing by microimmunofluorescence was done in 376 of 546 patients. All patients were negative for IgM antibodies. In the five PCR-positive patients, neither specific IgG nor IgA antibodies were found. Patients with CAP caused by C. pneumoniae had a lower median age (36 years) than the general study population (62 years). C. pneumoniae is currently a rare cause of CAP in adult patients in Germany. Analysis of a single serum sample is not useful for diagnosis of acute C. pneumoniae infection in CAP.     

Parainfluenza virus infection in adult bone marrow transplant recipients

The clinical course of parainfluenza virus infection occurring in 8 of 265 (3 %) adult bone marrow transplant recipients during 1991 was reviewed. Parainfluenza virus type 3 was isolated from all eight patients. The clinical course ranged from self-limited upper respiratory tract infections (2 patients) to severe lower respiratory tract disease (6 patients) associated with a 50 % mortality. This study highlights the important role of community respiratory viruses such as parainfluenza virus in the etiology of pneumonia in immunocompromised adults.     

Impact of rhinoviruses on pediatric community-acquired pneumonia

This study of 592 children seen in our Emergency Department with radiographically confirmed community-acquired pneumonia (CAP) was designed to evaluate the role of rhinoviruses (RVs) in the disease. The respiratory secretions of each child were assayed using RVP Fast in order to detect 17 respiratory viruses, and the RV-positive samples were characterised by means of real-time polymerase chain reaction and sequencing. RVs were identified in 172 cases (29.0%): 48/132 children aged<1 year (36.3%), 80/293 aged 1-3 years (27.3%), and 44/167 aged≥4 years (26.3%). Sequencing demonstrated that 82 RVs (49.1%) were group A, 17 (10.1%) group B, and 52 (31.1%) group C; 21 (12.2%) were untyped. RVs were found as single agents in 99 cases, and together with two or more other viruses in 73 (40.7%). There were only marginal differences between the different RV groups and between single RV infection and RV co-infections. RV CAP is frequent not only in younger but also in older children, and RV-A is the most common strain associated with it. The clinical relevance of RV CAP seems to be mild to moderate without any major differences between the A and B strains and the recently identified RV C.     

The aetiology and antibiotic management of community-acquired pneumonia in adults in Europe: a literature review

The purpose of this paper was to generate up-to-date information on the aetiology of community-acquired pneumonia (CAP) and its antibiotic management in adults across Europe. Structured searches of PubMed identified information on the aetiology of CAP and its antibiotic management in individuals aged >15 years across Europe. We summarise the data from 33 studies published between January 2005 and July 2012 that reported on the pathogens identified in patients with CAP and antibiotic treatment in patients with CAP. Streptococcus pneumoniae was the most commonly isolated pathogen in patients with CAP and was identified in 12.0–85.0 % of patients. Other frequently identified pathogens found to cause CAP were Haemophilus influenzae, Gram-negative enteric bacilli, respiratory viruses and Mycoplasma pneumoniae. We found several age-related trends: S. pneumoniae, H. influenzae and respiratory viruses were more frequent in elderly patients aged ≥65 years, whereas M. pneumoniae was more frequent in those aged <65 years. Antibiotic monotherapy was more frequent than combination therapy, and beta-lactams were the most commonly prescribed antibiotics. Hospitalised patients were more likely than outpatients to receive combination antibiotic therapy. Limited data on antibiotic resistance were available in the studies. Penicillin resistance of S. pneumoniae was reported in 8.4–20.7 % of isolates and erythromycin resistance was reported in 14.7–17.1 % of isolates. Understanding the aetiology of CAP and the changing pattern of antibiotic resistance in Europe, together with an increased awareness of the risk factors for CAP, will help clinicians to identify those patients most at risk of developing CAP and provide guidance on the most appropriate treatment.     

Prevalence of human respiratory viruses in adults with acute respiratory tract infections in Beijing, 2005–2007

To determine the aetiological role and epidemiological profile of common respiratory viruses in adults with acute respiratory tract infections (ARTIs), a 2-year study was conducted in Beijing, China, from May 2005 to July 2007. Nose and throat swab samples from 5808 ARTI patients were analysed by PCR methods for common respiratory viruses, including influenza viruses (IFVs) A, B, and C, parainfluenza viruses (PIVs) 1–4, enteroviruses (EVs), human rhinoviruses (HRVs), respiratory syncytial virus (RSV), human metapneumovirus (HMPV), human coronaviruses (HCoVs) OC43, 229E, NL63, and HKU1, and adenoviruses (ADVs). Viral pathogens were detected in 34.6% of patient samples, and 1.6% of the patients tested positive for more than one virus. IFVs (19.3%) were the dominant agents detected, followed by HRVs (6.5%), PIVs (4.3%), EVs (3.2%), and HCoVs (1.1%). ADVs, RSV and HMPV were also detected (<1%). The viral detection rates differed significantly between infections of the lower and upper respiratory tracts in the sample population: PIVs, the second most commonly detected viral agents in lower acute respiratory tract infections (LRTIs), were more prevalent than in upper acute respiratory tract infections, indicating that the pathogenic role of PIVs in LRTIs should be investigated. Currently, this study is the largest-scale investigation of respiratory virus infections in China with multiple agent detection, providing baseline data for further studies of respiratory virus infections in adults with ARTIs.     

Characterisation of winter respiratory viral infections in patients with asthma and COPD in Qatar

Respiratory viruses in patients with chronic obstructive pulmonary disease (COPD) or asthma have not been characterised in Qatar. This study aimed to identify the most common viral strains responsible for respiratory tract infections in asthma/COPD patients (without exacerbations) in Qatar during the winter season (2008-2009). Nasal swabs from patients with asthma/COPD and respiratory symptoms were evaluated for 15 common viruses. 200 adult patients (190 with asthma and 10 with COPD) were enrolled. Viral infections were present in 36 out of 200 patients (18 %). Cough and wheezing were the most common symptoms. Rhinovirus was the most common causative agent, followed by coronaviruses. Our findings confirm previous reports of rhinovirus prevalence in respiratory tract infections in asthma/COPD. A countrywide survey to confirm our findings is warranted.     

High incidence of rhinovirus infection in children with community-acquired pneumonia from a city in the Brazilian pre-Amazon region

Community-acquired pneumonia (CAP) is the leading cause of child death worldwide. Viruses are the most common pathogens associated with CAP in children, but their incidence varies greatly. This study investigated the presence of respiratory syncytial virus (RSV), adenovirus, human rhinovirus (HRV), human metapneumovirus (HMPV), human coronavirus (HCoV-OC43 and HCoV-NL63), and influenza A virus (FluA) in children with CAP and the contributing risk factors. Here, children with acute respiratory infections were screened by pediatrics; and a total of 150 radiographically-confirmed CAP patients (aged 3 months to 10 years) from two clinical centers in Sao Luis, Brazil were recruited. Patient's clinical and epidemiological data were recorded. Nasopharyngeal swab and tracheal aspirate samples were collected to extract viral nucleic acid. RSV, adenovirus, rhinovirus, FluA, HMPV, HCoV-OC43, and HCoV-NL63 were detected by real-time polymerase chain reaction. The severe CAP was associated with ages between 3 and 12 months. Viruses were detected in 43% of CAP patients. Rhinovirus infections were the most frequently identified (68%). RSV, adenovirus, FluA, and coinfections were identified in 14%, 14%, 5%, and 15% of children with viral infection, respectively. Rhinovirus was associated with nonsevere CAP (P = .014); RSV, FluA, and coinfections were associated with severe CAP (P < .05). New strategies for prevention and treatment of viral respiratory infections, mainly rhinovirus and RSV infections, are necessary.     

Clinical characteristics of acute viral lower respiratory tract infections in hospitalized children in Seoul, 1996-1998.

This study was performed to investigate the etiologic agents, age distribution, clinical manifestations and seasonal occurrence of acute viral lower respiratory tract infections in children. We confirmed viral etiologies using nasopharyngeal aspirates in 237 patients of the ages of 15 years or younger who were hospitalized for acute lower respiratory tract infection (ALRI) from March 1996 to February 1998 at Samsung Seoul Hospital, Seoul, Korea. The overall isolation rate was 22.1%. The viral pathogens identified were adenovirus (12.7%), influenza virus type A (21.1%), -type B (13.9%), parainfluenza virus type 1 (13.5%), -type 2 (1.3%), -type 3 (16.0%) and respiratory syncytial virus (21.5%). The occurrence of ALRIs was highest in the first year of life, although parainfluenza virus type 1 infection occurred predominantly in the second year of life and influenza virus caused illnesses in all age groups. The specific viruses are frequently associated with specific clinical syndromes of ALRI. The respiratory agents and associated syndromes frequently have characteristic seasonal patterns. This study will help us to estimate the etiologic agents of ALRI, and establish a program for the prevention and treatment. An annual nationwide survey is necessary to understand the viral epidemiology associated with respiratory illnesses in Korea.